IsFileOpen function not working correctly

I'm new to this form and hope you can help me. I found a "IsFileOpen" function and everything seemed to work perfectly. However, if serveral people try to use my code you will occationially get the message "File is now available" with the Read/Write and Cancel buttons. Is there a way to prevent this from happening. I don't want the many end users to get this message. I would just like them to get my message that says it's currently in use and try later. There are many IsFileOpen functions that I have found and they all function the same way. They work fine unless several users are using at the same time.

Any help would be most apprecitated! Thanks.

Post the code used in that function and the sub procedures that call it (if applicable).

Thanks, I tried it and it seems much better but I did still get the message to come up but less frequently. If you have any other suggestions I would appreciate your help!